Tramlines are open tracks intentionally left unseeded in fields of cultivated crops. They have become increasingly more important as markers or guides in the fields, while spraying herbicides or other chemicals, in order to eliminate spray overlaps and skips. With high cost, low dose chemicals, overlaps result in increased chemical cost and potential crop injury, while skips result in untreated areas. Also, tramlines enable spraying under poor lighting conditions and thereby make it possible to take advantage of cool, calm spraying conditions at dusk and/or at nighttime. Spraying at night or early morning is advantageous because less water is needed, as evaporation is less of a problem and dew may be taken advantage of. Further, the stoma openings on the plants' leaves are open, therefore less chemical is needed to provide the desired results. Further, as no seeds are planted in the tramlines, anything growing in the tramlines indicates the presence of weeds or other unwanted plants.
Also, and perhaps more importantly, tramlines are utilized as a pathway for wheels of agricultural implements. Tramlines permit taking multiple trips across a field without creating additional wheel tracks and therefore inhibits what would otherwise be excessive soil compaction over a widespread area. Also, driving on plants results in uneven maturation, which may be detrimental to the ability to readily harvest the crop. Accordingly, tramlines permit multiple trips across a field such as, for example, when top dressing nitrogen late in the season to boost yields and to enhance the protein content in a good year, or when applying fungicides and growth regulators, and the like, all without creating additional wheel tracks.
In the past, tramlines were generated by plugging certain dispensing units of planting drills, or by simply not having a dispensing unit installed at various points on the planter, corresponding to the rows where the tramlines were desired. However, the operating equipment was incapable of placing the tramlines in exactly the same location from year to year. Accordingly, prior art tramlining was not effective in preventing soil compaction.
Thus, a need exists to provide an apparatus and method for generating tramlines for the wheels of agricultural vehicles to follow, which would allow wheel tracks to be repeatedly run directly over the same unplanted rows, enabling improved spraying and cultivation.
The transfer of global positioning (GPS) technologies to civilian industry has greatly assisted in meeting financial challenges presented by today's precision agricultural needs. Systems typically achieve meter-level accuracy by utilizing differential GPS (DGPS) position corrections transmitted from fixed base stations through, for example, moving map displays. Such systems allow for navigation and guidance of farm implements and systems using DGPS for applying fertilizers, herbicides and pesticides. However, such systems have generally been limited in their capabilities.